WebSphere V9 "Traditional" Now Java EE 7 Certified
Given the very large and loyal customer base IBM has as well as the continued substantial usage rates for WebSphere traditional, this is sure to be a further boost to Java EE 7 adoption. In particular it is important to note that WebSphere V9 also comes with support for Java SE 8.
WebSphere V9 joins the Java EE 7 compatible ranks of JBoss EAP 7, GlassFish 4, WildFly, WebSphere Liberty Profile 188.8.131.52, WebLogic 12.2.1, Hitachi Cosminexus and TmaxSoft JEUS. All of the Java EE certified offerings are always listed on the official Java EE compatibility page. For some perspective few other open standards such as SQL have as many available implementations as Java EE 7 already has (and this is bound to only just keep getting better).
Other than existing WebSphere traditional customers it is honestly difficult to recommend it over WebSphere Liberty. Whatever you may think of the WebSphere brand, you will be doing yourself a disfavor if you do not take WebSphere Liberty seriously. You should definitely not let any open source prejudices unduly hinder your appreciation of the engineering work behind Liberty. It is definitely one of the most modular, lightweight and impressive performing (in every way) modern application platforms available today - Java EE or otherwise. Hopefully that is food for some thought...